[StuartT]

I came back yesterday and left my '03 DHS with 96K miles running, at operating temperature in park and checked my ATF. It was bubbling near the top above the full level. I used a large syringe and removed about 2 ounces of the Dexron III to lower it to the full mark (and it stopped bubbling as well). About three hours later, when nearly stone cold, I checked the level again with the engine off. Nothing on the stick. In fact, there was no fluid visible at the bottom of the reservoir cavity.

I added a little over a quart of ATF to get the fluid level back up to the bottom of the dipstick cold zone, still 4 or 5” below the full mark to allow for expansion. Then I started the engine with the fill cap off. The fluid immediately rose to within an inch of the top of the filler hole which is above the full level, and I was worried it was going to overflow, so I put the cap back in place. Now I don’t know what to do. This is not acting like any transmission I have ever seen.

The transmission operation is smooth and predictable although I do have a slightly leaking 3^rd clutch seal I think it’s called. Anyone have an idea what might be going on and how I should set the fluid level?

 

[MoistCabbage]

Transmission fluid is checked and adjusted with the drivetrain hot (10 mile/20 minute drive) and idling. Furthermore, the transmissions in these cars are dry sump. No fluid should be visible on the dipstick with the engine off.

 

[Submariner409]

Yep ^^^ - perfect advice - dry sump transmission, no fluid on the stick with the engine off.

Bubbles - dry sump transmission - the scavenge pumps try to keep the pan dry with the engine running, so they pump more fluid than the pressure supply pump - bubbles in the upper tank are perfectly normal.

Keep your hot fluid level in the middle of the dipstick hashmark, engine running in P on a level surface. HOT = greater than a 15 mile drive.

When all else fails, read the GM service manuals.

 

[Ranger]

About three hours later, when nearly stone cold, I checked the level again with the engine off. Nothing on the stick. In fact, there was no fluid visible at the bottom of the reservoir cavity.

It ALL drains back into the pan when shut down. That's normal.

I added a little over a quart of ATF to get the fluid level back up to the bottom of the dipstick cold zone

You overfilled it again.

 

[davester]

Yes, this is really an RTFM. It'll say exactly how you should check the level of all your fluids.

Pretty much all automatic transmissions require the car to be level, engine to be running, transmission in park, to check the transmission's fluid level.
Some require you to shift briefly into each gear, some have a specified warmup-period.

Read the Owners Manual. If you don't have one, you should be able to download a PDF of it from somewhere for free.

 

[StuartT]

I appreciate the feedback and guidance and removed the excess fluid from the tranny. All is well now and I learned something.